Your search for "Water flow parts" revealed the following:

Stainless steel pipe 0.7mm OD 0.5mm ID 0.5mm : Sakatsu Material Non-scale 4653

Fog generator module option water supply wick (3 pcs.) : BitTradeOne Material Non-scale MMSTGN-OP1

Hexagon Socket Head Fittings Double 1.5mm dia. with Taper : Sakatsu Detail Up Non-scale 4460

Stainless steel pipe, outer diameter 2.0mm, inner diameter 1.7mm : Sakatsu material, Non-scale 4659

Hexagon Socket Head Fittings, 1.2mm Flat, Tapered : Sakatsu Detail Up Non-scale 4463

Hexagon Socket Head Fittings Double 1.2mm Flat, Tapered : Sakatsu Detail Up Non-scale 4462

Introductory Material Set: River and Waterfall - Woodland Material - Non-scale LK955

Hexagon Socket Head Fittings, Double Dia. 1.8mm Flat, Tapered : Sakatsu Detail Up Non-scale 4458

Curved embankment parts - basic part (2 pieces): Molin material TM-11

Bugbear Chieftain : HERMIT INN Unpainted Kit Non-scale HM007

Stainless steel pipe, outer diameter 1.2 mm, inner diameter 1.0 mm : Sakatsu Material non-scale 4657

Air Funnel 2.6-3.0 4pcs: Sakatsuo Detail Up 1:24 3210

Code Outer diameter approx. 1.2 mm Red colour : Sakatsu Material Non-scale 4518

Hexagonal pipe joint, double flat 1.5mm : Sakatsu Detail Up Non-scale 4452

Rail joiner for code 65, 24 pcs: Atlas Kit N (1:160) 2490

Grass by the water - Summer : Miniatures Nature Materials Non-scale 739-22

Plants by the water 17 bundles : Noch Plant material, non-scale 14052

Water surface creation material set for ponds : Morin material - Non-scale 603

Small wooden bridge: Noch assembly kit HO (1:87) 14222

Riveted Sill Header Set: Echo Model Unpainted Kit HO (1:80) 1695